I have Shopify store that has over 3 thousand categories/subcategories and thousands of products. My store speed performance is slow.

I have hired developers who have implemented various techniques, tools, liquid image apps, coding and so forth. Store performance did not improve much and is still currently very slow compared to what is required in order to operate efficiently and productively,

I am looking for someone who can make my store operate as if it is being hooked up to a Dedicated Server and load pages instantly. Keep in mind that all sorts of tools have been already worked on to no available. The speed got just a bit better, but not good enough to support a business/sales since customers leave the pages due to being impatient and it is understandable,

If there are any new tools and/or techniques that can actually make my store/pages load instantly just like with Dedicated Server services, I would love to know and work with you,

For example you could build your storefront out as a custom web app, then communicate with your shop via the Shopify API.

That gives you 100% control over your server + architecture and you can do things like cache pages and create the best solution for your individual store (rather than a theme that is used by many). It's more expensive than regular Shopify hosting but it's an option.

Another solution to help improve speed is to build a custom theme that's focused on performance, but that won't get you instantly loaded pages.

You can optimize your theme to help your load speed, this won't make pages load instantly but can help the user experience for mobile users or those on a slower connection. Here's a tool we built for analyzing and optimizing Shopify sites: Shopify Analyzer.

@JonWright 's suggestion about AMP works well if speed is your primary goal - these apply to mobile pages coming from Google search but can load them near instantly. You can probably set that up on your own: speedboostr.com/shopify-amp-guide.